1. Field of the Invention
The present invention relates to an image information transmission apparatus that parallelizes and transmits encoded stream data, and more particularly to an image information transmission apparatus that parallelizes and transmits CABAC stream data that has undergone adaptive binary arithmetic coding based on the H.264 standard.
2. Description of the Related Art
Conventionally, when transmitting CABAC stream data (hereunder, may be referred to simply as “CABAC stream”) that has undergone context adaptive binary arithmetic coding (hereunder, referred to as CABAC: Context Adaptive Binary Arithmetic Coding) based on the H.264 standard, a stream transmitting apparatus sends the CABAC stream as a single stream to a CABAC decoding section. The CABAC decoding section on the receiving side is thus required to receive the single CABAC stream and perform decoding processing in real time.
Generally, when a CABAC stream is decoded, a decoding operation at a certain decoding point within a bit string of an encoded stream is dependent on context information that has been continuously changed during the preceding decoding operations. Accordingly, when a bit string of a stream that has been encoded using CABAC is decoded, it is necessary to perform decoding sequentially from the start of the bit string while updating context information. This is a factor that hinders parallelization of CABAC decoding processing and decreases the overall decoding processing performance of an image decoding apparatus.
Examples of a conventional information processing apparatus that performs this kind of parallel decoding processing of a CABAC stream include an apparatus that performs control such that a plurality of arithmetic decoding means individually refer to header information stored in a memory region to independently perform arithmetic decoding processing of a plurality of data slices (for example, see Japanese Patent Application Laid-Open Publication No. 2007-295392).
However, the apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2007-295392 is an apparatus that divides encoded stream data into slice units and performs parallel decoding processing thereon, and is not one that divides encoded stream data at arbitrary positions to perform parallel transmission and parallel decoding processing.